Oh, they've known about black lung since long before your grandfather. I never met my maternal grandfather, who worked the seams of southeastern Ohio — and walked about to do other short-term jobs, such as making brake shoes (asbestos) and stirring open vats of early plastics (everybody's guess) to feed his wife and 7 children through the Great Depression. When Mother was herself dying of pancreatic cancer (common among the children of coal miners) and told me his history, I asked, "How could he have not died young of lung cancer?!"
Grandfather Vane's father, also a coal miner, managed to avoid it and live to 101. I don't know about Grandma's father, who immigrated from Italy as a callow youth in the late 19th c, probably as a scab. But it's known that the striking miners didn't hold the scabs' desperation against them, and the family story goes that he stayed and became a citizen because he so admired the strength of the unions here. He did survive one wife and father a whole 2nd family. Vane and Rose kept their 4 sons out of the mines. All but 2 of their children (yes, daughters) completed college, one on a football scholarship and the others on their intellect alone. Two of them became teachers.
I am so ashamed of my country's shortsightedness about finite resources, and about the infinite resources of those who give their lives to extract the others.